Minneapolis police said Tuesday that three men have been arrested in connection with an apparently racially motivated shooting that left five members of the Black Lives Matter movement hospitalized on Monday night.

The Minneapolis Star Tribunereports Allen Lawrence “Lance” Scarsella III, 23, was arrested in Bloomington, while 21-year-old Nathan Gustavsson of Hermantown and Daniel Macey, 26, of Pine City, were taken into custody after they turned themselves in. All three men are white.

The incident began at around 10:45 p.m. when, according to Miski Noor of Black Lives Matter, “a group of white supremacists,” at least one of whom was wearing a mask, “showed up at the protest, as they have done most nights.” When protesters tried to herd the group away, Noor said at a press conference that they “opened fire on about six protesters,” hitting five of them. One demonstrator said the assailants used “police tactics.”

The victims, all black men ages 19-43, were taken to local hospitals with non life-threatening injuries. One victim, who was shot in the stomach, required surgery.

Witnesses said police used Mace on journalists, activists and bystanders. One activist, 25-year-old Alexander Clark, told the New York Times that four nearby officers stood by during the shooting.

“They sat here and watched,” said Clark. “Not one of the officers came off the wall. We all said, ‘Why aren’t you doing anything?’” The officers allegedly told protesters not to talk to them, adding, “this is what you all wanted, right?”

Noor also accused officers of making “disparaging comments to those at the protests instead of taking the threat seriously.” She told reporters that local Black Lives Matter protesters “have zero faith in this police department’s desire to keep our community safe.”

Black Lives Matter activists have been camped outside a police precinct on Morgan Ave. N. since November 15, after police fatally shot 24-year-old unarmed black man Jamar Clark. Witnesses claim Clark was handcuffed at the time he was shot; police deny these allegations.The Black Lives Matter protesters have been demanding authorities release video footage of the incident, but have so far been rebuffed by federal, state and local officials.

Noor called the shooting attack “an act of terrorism” and vowed to keep protesting. Nearly 1,000 demonstrators marched on city hall on Tuesday to protest the shooting and to demand justice.

“If we can get through this, we can get through anything,” protester Jie Wronski-Riley told the Twin Cities Pioneer Press. “Black Lives Matter will not be standing down. We will not be silenced.”

An FBI spokesperson said the bureau is working with local police to determine if a hate crime occurred and whether federal intervention is needed. Law enforcement officials said they were aware of a video showing masked men brandishing a pistol while making racist remarks and justifying the killing of Jamar Clark.

Monday’s shooting came days after Black Lives Matter activist Mercutio Southall Jr. was beaten and kicked by a group of white men for interrupting Republican presidential frontrunner Donald Trump at a Mobile, Alabama campaign event. Trump then defended his supporters for brutalizing Southall, saying “maybe he should have been roughed up” for being “so obnoxious and so loud.”